<form method="post">
  <div class="uiAdminMainForm">
    <div class="uiFieldWrap">
      <div class="uiFieldLabel">Name:</div>
      <div class="uiField">
        <input value="<?php echo @$_POST['nav_name'] ?>" name="nav_name" type="text" maxlength="50" />
      </div>
    </div>
    <div class="uiFieldWrap">
      <div class="uiField">
        <input type="submit" />
      </div>
    </div>
  </div>
</form>